Category Archives: Coreidae

This is an insect many people in the United States and Europe may be familiar with; perhaps not by name, but certainly by appearance. Known as Leptoglossus occidentalis, the Western conifer seed bug, its large (20 mm) size, tendency to wind up in houses, and habit of releasing a strong scent when disturbed or crushed have shocked many of us. However, there is no need to be concerned with these creatures, as they are completely harmless to humans and pets, and cannot reproduce indoors. The only reason they enter our homes is because they are looking for a warm place to spend the winter. Ordinarily they would overwinter under leaf litter or under bark, but human habitations are just too warm to resist; unfortunately for them, as most people do not appreciate their presence. During the summer months, their nymphs are high up in conifer trees, feeding on sap. Usually they do not cause much harm, but they sometimes damage conifer nurseries.

A very young nymph, final instar nymph, and resulting adult of Leptoglossus occidentalis (Kennebunk, ME).

This is an insect on the move. It is originally native to western North America, but started spreading eastward in the 1950s and is now common coast to coast. It was reported in Italy in 1999 and has since taken up residence across much of the European continent as well. There, it has the potential to become a more serious pest because it has no native enemies.

L. occidentalis is a member of the family Coreidae, the leaf-footed bugs. This name refers to the expanded portions of the hind legs, which in some tropical species are expanded enough so that they really do look like leaves. Coreidae is a colorful and diverse family, with approximately 1,900 species worldwide. The genus Leptoglossus includes about 60 species, eleven of which can be found in the U.S. and Canada. I have been fortunate enough to see four species of Leptoglossus, although the overwhelming majority have been L. occidentalis.

Leptoglossus oppositus. I have seen this species in Maryland and New York; this individual is from Bear Mountain State Park, NY. It feeds on many different plants but is partial to catalpa.

Leptoglossus phyllopus. The straight white cross-bar identifies this species. Supposedly one of the most common eastern species, though I’ve only seen it once, in Florida. It can be a pest of many crops.

Leptoglossus gonagra. In my opinion the coolest of the Leptoglossus species I’ve encountered, these have bright yellow spots on the ventral surface and a bow-legged appearance. They are a pantropical species, sometimes damaging citron groves in Florida. This was one of a pair of individuals sent to me from Fort Lauderdale, FL.

Side note: I have recently acquired Photoshop, and this post was partially borne out of one of my first experiments, the L. occidentalis collage, the style of which is based upon Piotr Naskrecki’s collages on white (such as this one).